The present invention relates to an improved control mechanism for use in a magnetically operated wheel. It mainly is made up of an outer cover, an inner housing, a pair of compression springs, two small supporting wheels, two linkage pieces, an externally connected pull cord control mount, a sensor, a signal transmitter mount and an internal or external transmission set. In adjustment, only a motor is activated to make a main transmission device, a secondary transmission device, a driven gear, a restraint unit and a driving wheel rotate in synchronism. Besides, when the driving wheel rotates, a lower gear and the linkage rack of the two pivotal linkage pieces equipped with a plurality of magnets and housed in a flywheel are in mesh engagement with each other to vary the distance between the magnets and the flywheel so as to make the adjustment of braking resistance of the flywheel in a stageless manner.
People living in a modern society are busy with their work and seldom have time to engage in outdoor physical exercise, so many of them attend indoor health clubs to maintain their physical fitness by means of various types of exercise equipment. Taking an exercise bike for example, it is mainly equipped with a magnetically operated wheel which is made of magnetic material (such as iron) and has a set of magnets housed therein. By way of a closed magnetic field built up between of the magnets and the wheel of magnetic material, a braking resistance is formed to stop the magnetically operated wheel to rotate. Thereby, the variation of the distance between the magnets and the magnetically operated wheel can produce different brake resistance, resulting in generation of various physical exercise level for different people.
Referring to FIG. 1, a conventional control mechanism of the magnetically operated wheel is illustrated in explosion. It is comprised of a flywheel 10, two inner wheel mounts 20, two brake plates 21, two wire guide rollers 22, two compression springs 23, two positioning seats 24 and a wheel shaft 30. The flywheel 10 has an open-topped chamber 11 with a hollow axle hole 12 defined at the center thereof and four through holes 13 positioned around the central axle hole 12. Each of the inner wheel mounts 20 has a raised platform 201 having a central shaft hole 202 at the center thereof with a pair of rectangular spring receiving chambers 203 and a wire receiving slot 204 on the outer peripheral edge thereof. Adjacent to each spring receiving chamber 203 and on the inner side of the inner wheel mount 20 is disposed a stop post 205. Two symmetric locking posts 206 are located at opposite edges of the wheel mount 20. On both sides of only one of the locking post 206 is disposed a pivot stem 207 each having a hole 208. Next to the other locking post 206 is located a two staged insertion post 209. Around the central shaft hole 202 are disposed four locking holes 2021. Each braking plate 21 is in a curved form with a plurality of magnets 211 secured to the outer surface thereof and has a wire hole 212 at one end and an H-shaped extension unit 213 having a pivot edge 214 smaller than the inner diameter of the hole 208 at the other end. Each positioning seat 24 has a shaft hole 241 at the center with four locking holes 242 on its base board. The wheel shaft 30 has two threaded ends 301.
The flywheel 10 and the inner wheel mounts 20 are integrally joined together with the brake plates 21 housed between the wheel mounts 20. The positions of the brake plates 21 can be adjusted to vary the brake resistance of the conventional magnetically operated wheel as a result of the variation of the magnetic attraction of the magnets 211 on the flywheel 10. The brake plates controlled by the wire A can be pivoted adjusted as the end of the wire A is pulled outwardly as shown in FIG. 2. Such a prior art structure has a disadvantage in operation. The wire A must be pulled with effort to pivot both the brake plates 21, resulting in easy breaking of the wire A or getting-stuck in operation.
Therefore, the primary object of the present invention is to provide an improved control mechanism for use in a magnetically operated wheel which drives in linkage the respective wheels by way of a motor so as to permit the magnetically operated wheel not only to be adjusted in a stageless manner without any restraint but also effectively increase the applied force and reduce the resistance by way of a torsion limiting security device and an effort saving level. Even the microcomputer control is out of order, the wheel will not be damaged whereby the magnetically operated wheel can be fully performed to its limit.